Pleura & peritoneum
General
Anatomy, history, grossing & features to report
Author: Vaidehi Avadhani, M.D.
Last author update: 1 December 2013
Last staff update: 23 June 2023
Copyright: 2003-2023, PathologyOutlines.com, Inc.
PubMed Search: Pleura normal histology
Table of Contents
Anatomy | Drawings | Histology | Mesothelial cells | Connective tissue cells | Black spots | Types of specimen | Surgical procedures definition | Grossing biopsy | Grossing pleurectomy | Features to reportCite this page: Avadhani V. Anatomy, history, grossing & features to report. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pleurahistology.html. Accessed September 25th, 2023.
Anatomy
- Lungs are surrounded by visceral pleural, a delicate serous membrane arranged as a closed invaginated sac
- Inner chest cavity is lined by parietal pleural membrane
- Visceral and parietal pleura define the pleural space / cavity, which normally has minimal volume, unless lungs collapse or air / fluid collects between the 2 layers
- Only minimal contact between right and left pleural sacs
- Regional lymph nodes are internal mammary, intrathoracic, scalene and supraclavicular
Drawings
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Pleura and chest wall
Histology
- Lined by mesothelial cells overlying vascularized connective tissue
- Mesothelium provides smooth, low friction surface to facilitate the gliding motion of lungs in pleural cavity, heart in pericardial cavity, viscera in abdominal cavity
- Gliding facilitated by numerous surface microvilli, thick glycocalyx, secretion of hyaluronic acid and other glycosaminoglycans
Mesothelial cells
- Microscopic (histologic) description
- Monolayer of flat or low cuboidal cells with bland and uniform nuclei, fine delicate chromatin, inconspicuous nucleoli
- In fine needle aspirates, have well defined cytoplasm and distinct cell borders
- Positive stains: keratin
- Electron microscopy description: apical tight junctions, desmosomes, surface microvilli, cytoplasmic tonofilaments in bundles
Connective tissue cells
Black spots
- Carbonaceous / anthracotic pigments in parietal pleura
- Present in > 90% of urban dwellers in Belgium at autopsy
- Not related to hyaline pleural plaques (Am J Surg Pathol 2002;26:1198)
- Associated with lymphatic drainage
- Microscopic (histologic) description: deposits of opaque particles (intra or extracellular) of various sizes under an intact mesothelial layer, associated with chronic inflammatory cells
Types of specimen
- Biopsy
- Pleurectomy
Surgical procedures definition
- Pleurectomy / decortication with mediastinal lymph node sampling
- Complete removal of pleura and all gross tumor
- Extrapleural pneumonectomy
- En bloc resection of pleura, lung, ipsilateral diaphragm; may include pericardium
Grossing biopsy
- If received for frozen section, ensure enough lesional tissue is present
- Ask for additional tissue if tissue submitted needs to be entirely frozen
- Important because immunohistochemistry may be unreliable on previously frozen tissue
- May need to send for special studies including electron microscopy and cytogenetics
Grossing pleurectomy
- Describe dimension and number of fragments, any lesions present
- Note if pleural plaques are seen; describe
- Tumor involvement of adjacent structures - lung, diaphragm, pericardium, skeletal muscle
- Ink margins in sections closest to tumor
- Tumor
- One section per cm of tumor
- Extensive sampling if desmoplastic mesothelioma is suspected
- Additional sections of lung, if present (for asbestos fiber analysis)
- Recommended (up to 5)
- Sections for ancillary tests
- Electron microscopy, cytogenetics, etc., if necessary
- Lymph nodes
- References: NCCN: NCCN Guidelines [Accessed 23 March 2018], Lester: Manual of Surgical Pathology, 3rd Edition, 2010
Features to report
- Tumor size and location
- Histologic type
- Extent of invasion
- Surgical resection margins
- Involvement of pleura, pulmonary vessels, bronchus, mediastinal structures, diaphragm, chest wall, other
- Lymph nodes: total examined, number involved by tumor, extracapsular extension
- Presence of pleural plaques, ferruginous bodies, pulmonary interstitial fibrosis, other significant findings
